Geology topics

Zachary R. Laughrey

Publications and source records attributed to Zachary R. Laughrey.

9 recordsLinked to original sources

USGS2026

Diverse cyanopeptides follow distinct temporal succession patterns in freshwater harmful algal blooms

Toxic cyanobacterial harmful algal blooms (cyanoHABs) threaten freshwater resources globally and are intensifying with increasing eutrophication. Bloom toxicity is strongly influenced by intraspecific variation in the biosynthetic repertoires of toxic cyanobacteria, yet few studies examine the diversity of cyanobacterial cyanopeptides beyond hepatotoxic microcystins . To understand the dynamics and drivers of cyanopeptide diversity in cyanoHABs, we analyzed temporal patterns of cyanobacteria, metabolites, and their biosynthetic gene clusters (BGCs) in western Lake Erie using a 7-year time series (2016–2022) of metagenomic and metabolomic data. Our findings demonstrate that shifts from Microcystis to Dolichospermum occur later in the bloom season, coinciding with lower temperatures. Modules of co-varying BGCs (biosynthesis modules) from these genera were identified with hierarchical clustering, with uncharacterized BGCs among the most abundant. Biosynthesis modules rich in nonribosomal peptide synthetases (NRPS) peaked in early August, coinciding with elevated levels of inorganic nitrogen, warmer temperatures, and high Microcystis abundance. In contrast, modules rich in polyketide synthases (PKS) and ribosomally synthesized and post-translationally modified peptides (RiPPs) peaked following the Microcystis maximum in mid-August. Metabolomic analyses confirmed that metabolites followed shared seasonal patterns with their associated biosynthesis modules, forming three phases characterized by (i) microcystins, (ii) anabaenopeptins and aeruginosins, and (iii) aerucyclamides. These phases co-varied with bottom-up and top-down pressures, with later phases coinciding with increased microbially processed organic nitrogen and reduced detection of grazers. This study demonstrates consistent seasonal patterns of cyanobacterial metabolite succession and co-occurrence beyond microcystins, suggesting tradeoffs between biosynthetic resource demands and ecological controls.

Ohio↗

USGS2025

Comparison of Microcystin-LR degradation by UV222 and UV254

Microcystin-LR (MC-LR), a toxin produced during some cyanobacterial harmful algal blooms (cyanoHABs), can harm ecosystems and require consideration in water treatment. Ultraviolet (UV)-C treatment has the potential to degrade cyanotoxins with less harmful byproducts than other treatments. This study compares MC-LR degradation in three different water types using UV-C light emitted from a krypton-chlorine excimer lamp (UV light at 222 nm, UV 222 ) or a low-pressure (LP) Hg lamp (UV light at 254 nm, UV 254 ). Quantitative analyses by enzyme-linked immunosorbent assay (ELISA), ultra-performance liquid chromatography with photodiode array detection (UPLC-PDA), and high-performance liquid chromatography-high-resolution mass spectrometry (LC-HRMS) demonstrated that UV 222 had a degradation rate constant 2.4–4.2 times greater than UV 254 . This aligns with the MC-LR molar absorption (ε) and quantum yield (Φ) in deionized (DI) water. LC-HRMS revealed the photoisomer concentration increasing with UV dose. Trends of abundant photoisomers indicate further degradation. Together, these trends indicate UV 222 is a more complete pathway toward protein phosphatase inhibition 2A (PP2A) inactive compounds than UV 254 . Electrical energy per order ( E EO ) for UV 222 and UV 254 was similar across all water matrices and analytical methods, demonstrating that UV 222 has the potential to surpass the degradation and electrical efficiency of UV 254 used in water disinfection.

Environmental Science and Technology↗

USGS2025

Cyanotoxin and domoic acid occurrence, relation with salinity, and potential recreational health risks in U.S. coasts in the 2015 US EPA National Coastal Condition Assessment

In the first nationwide study of cyanotoxins in U.S. estuaries, algal toxins, cyanotoxins, chlorophyll, and salinity were measured in samples collected during the National Coastal Condition Assessment 2015. Anatoxin-a (ANAA), cylindrospermopsin (CYLS), domoic acid (DMAC), and microcystins (MCs) were detected by LC/MS/MS in 0.6, 0.9, 8.3, and 2.0 % of samples with mean concentrations of detections of 0.13, 0.13, 0.53, and 0.49 µg/L, respectively. MCs by ELISA were also evaluated, and 4.0 % of samples had measurable MCs with a mean of 0.78 µg/L. While ANAA and CYLS were detected south of 40° latitude, MCs by ELISA and DMAC occurred nationwide. Results were compared to freshwater recreational health thresholds from the World Health Organization and US Environmental Protection Agency to evaluate potential recreational exposure to MCs and CYLS since marine thresholds do not currently exist. Cyanotoxins were categorized using the 2021 World Health Organization Alert Level Framework for recreational exposure with 99.4, 99.1, 94.7, 98.0, and 44.7 % of samples being at the Vigilance Level for ANAA, CYLS, MCs (ELISA and LC/MS/MS), and chlorophyll, respectively with the remaining samples at Alert Level 1. Chlorophyll had 19.9 and 9.9 % of samples at Alert Level 1 and Alert Level 2, respectively. All cyanotoxins were below US EPA health advisory thresholds. ANAA, CYLS, DMAC, and MCs by ELISA were detected in samples with a wide range of salinities, while MCs by LC/MS/MS only occurred in samples with salinity <5 part per thousand (PPT). The source of cyanotoxins is likely a combination of inland transport and in situ estuarine production.

contiguous United States↗

USGS2022

Corrigendum: Associations between cyanobacteria and indices of secondary production in the western basin of Lake Erie

In the last year, we became aware that data used in our above-referenced manuscript from 2018 published in Limnology and Oceanography contained significant errors. In the 2018 manuscript, we found that indices of secondary production were negatively correlated to indices of cyanobacterial abundance and toxicity. Unfortunately, one of our indices of cyanobacterial abundance (biovolume) and our measurement of toxicity (microcystin concentration) were inaccurate in the data we used in the 2018 manuscript. Upon discovering these errors, we immediately began correcting the repositories where these data were available. Having corrected those data repositories, we are now reporting on the re-analysis of the data using the methods previously described in the 2018 manuscript. Although the relationships are slightly different, our interpretation is that the conclusions of the 2018 manuscript are still valid using the corrected data. The data errors we experienced were traced to a spreadsheet that was used to share data among the research team, which had errors caused by mistakes in copy-pasting formulas instead of data and ‘inadvertent’ edits that were saved by the spreadsheet's auto-save function. We apologize to the scientific community for these errors.

Lake Erie↗

USGS2021

A review of algal toxin exposures on reserved federal lands and among trust species in the United States

Associated health effects from algal toxin exposure are a growing concern for human and animal health. Algal toxin poisonings may occur from contact with or consumption of water supplies or from ingestion of contaminated animals. The U.S. Federal Government owns or holds in trust about 259 million hectares of land, in addition to the Trust species obligations. We completed the first comprehensive review of potential toxin-producing algal blooms in surface waters on Federal lands and Trust species exposed to algal toxins. Events were sorted into three tiers based on potentially toxic algae abundance or toxin concentration and related effects on animal morbidity and mortality. At least 11.1% of Federal lands are known to have been affected by algal events, but exposure is likely underreported. The occurrence of potential toxin producers and their toxins (Tier 1) have been documented 337 times, health advisory threshold exceedances (Tier 2) were reported 943 times, and 86 events involved animal sickness or death linked to cyanobacteria or marine toxins (Tier 3). Trust species exposed to cyano- or algal toxins included marine mammals, migratory birds, threatened and endangered species, and species of concern. We report numerous data gaps ranging from potential effects on human health from consuming intoxicated animals to the infrequency of measuring and reporting certain toxins. Improvements to field and laboratory methods, more consistent evaluation of toxin exposure, decreased latency on data analysis, delivery and interpretation will be necessary to improve response and management strategies for protecting human and animal health where issues persist.

Critical Reviews in Environmental Science and Tech↗

USGS2021

Neither microcystin, nor nodularin, nor cylindrospermopsin directly interact with human toll-like receptors

Various stressors including temperature, environmental chemicals, and toxins can have profound impacts on immunity to pathogens. Increased eutrophication near rivers and lakes coupled with climate change are predicted to lead to increased algal blooms. Currently, the effects of cyanobacterial toxins on disease resistance in mammals is a largely unexplored area of research. Recent studies have suggested that freshwater cyanotoxins can elicit immunomodulation through interaction with specific components of innate immunity, thus potentially altering disease susceptibility parameters for fish, wildlife, and human health owing to the conserved nature of the vertebrate immune system. In this study, we investigated the effects of three microcystin congeners (LR, LA, and RR), nodularin-R, and cylindrospermopsin for their ability to directly interact with nine different human Toll-like receptors (TLRs)—key pathogen recognition receptors for innate immunity. Toxin concentrations were verified by LC/MS/MS prior to use. Using an established HEK293-hTLR NF-κB reporter assay, we concluded that none of the tested toxins (29–90 nM final concentration) directly interacted with human TLRs in either an agonistic or antagonistic manner. These results suggest that earlier reports of cyanotoxin-induced NF-κB responses likely occur through different surface receptors to mediate inflammation.

Chemosphere↗

USGS2021

Multiple co-occurring and persistently detected cyanotoxins and associated cyanobacteria in adjacent California lakes

The global proliferation of toxin producing cyanobacterial blooms has been attributed to a wide variety of environmental factors with nutrient pollution, increased temperatures, and drought being three of the most significant. The current study is the first formal assessment of cyanotoxins in two impaired lakes, Canyon Lake and Lake Elsinore, in southern California that have a history of cyanobacterial blooms producing high biomass as measured by chl-a. Cyanotoxins in Lake Elsinore were detected at concentrations that persistently exceeded California recreational health thresholds, whereas Canyon Lake experienced persistent concentrations that only occasionally exceeded health thresholds. The study results are the highest recorded concentrations of microcystins, anatoxin-a, and cylindrospermopsin detected in southern California lakes. Concentrations exceeded health thresholds that caused both lakes to be closed for recreational activities. Cyanobacterial identifications indicated a high risk for the presence of potentially toxic genera and agreed with the cyanotoxin results that indicated frequent detection of multiple cyanotoxins simultaneously. A statistically significant correlation was observed between chlorophyll-a (chl-a) and microcystin concentrations for Lake Elsinore but not Canyon Lake, and chl-a was not a good indicator of cylindrospermopsin, anatoxin-a, or nodularin. Therefore, chl-a was not a viable screening indicator of cyanotoxin risk in these lakes. The study results indicate potential acute and chronic risk of exposure to cyanotoxins in these lakes and supports the need for future monitoring efforts to help minimize human and domestic pet exposure and to better understand potential effects to wildlife. The frequent co-occurrence of complex cyanotoxin mixtures further complicates the risk assessment process for these lakes given uncertainty in the toxicology of mixtures.

California↗

USGS2020

Mixed organic and inorganic tapwater exposures and potential effects in greater Chicago area, USA

Safe drinking water at the point of use (tapwater, TW) is a public-health priority. TW exposures and potential human-health concerns of 540 organics and 35 inorganics were assessed in 45 Chicago area United States (US) homes in 2017. No US Environmental Protection Agency (EPA) enforceable Maximum Contaminant Level(s) (MCL) were exceeded in any residential or water treatment plant (WTP) pre-distribution TW sample. Ninety percent (90%) of organic analytes were not detected in treated TW, emphasizing the high quality of the Lake Michigan drinking-water source and the efficacy of the drinking-water treatment and monitoring. Sixteen (16) organics were detected in >25% of TW samples, with about 50 detected at least once. Low-level TW exposures to unregulated disinfection byproducts (DBP) of emerging concern, per/polyfluoroalkyl substances (PFAS), and three pesticides were ubiquitous. Common exceedances of non-enforceable EPA MCL Goal(s) (MCLG) of zero for arsenic [As], lead [Pb], uranium [U]), bromodichloromethane, and tribromomethane suggest potential human health concerns and emphasize the continuing need for improved understanding of cumulative effects of low-concentration mixtures on vulnerable sub-populations. Because DBP dominated TW organics, residential TW concentrations are potentially predictable with expanded pre-distribution DBP monitoring. However, several TW chemicals, notably Pb and several infrequently detected organic compounds, were not readily explained by pre distribution samples, illustrating the need for continued broad inorganic/organic TW characterization to support consumer assessment of acceptable risk and point-of-use treatment options.

Illinois↗

USGS2017

Associations between cyanobacteria and indices of secondary production in the western basin of Lake Erie

Large lakes provide a variety of ecological services to surrounding cities and communities. Many of these services are supported by ecological processes that are threatened by the increasing prevalence of cyanobacterial blooms which occur as aquatic ecosystems experience cultural eutrophication. Over the past 10 yr, Lake Erie experienced cyanobacterial blooms of increasing severity and frequency, which have resulted in impaired drinking water for the surrounding communities. Cyanobacterial blooms may impact ecological processes that support other services, but many of these impacts have not been documented. Secondary production (production of primary consumers) is an important process that supports economically important higher trophic levels. Cyanobacterial blooms may influence secondary production because cyanobacteria are a poor‐quality food resource and cyanotoxins may be harmful to consumers. Over 3 yr at 34 sites across the western basin of Lake Erie, we measured three indices of secondary production that focus on the dominant bivalve taxa: (1) growth of a native unionid mussel, (2) the size of young‐of‐year dreissenid mussels, and (3) the mass of colonizing animals on a Hester‐Dendy sampler. Associations between these indices and cyanobacterial data were estimated to assess whether cyanobacteria are associated with variation in secondary production in the western basin of Lake Erie. The results suggest cyanobacterial abundance alone is only weakly associated with secondary production, but that cyanotoxins have a larger effect on secondary production. Given recurring late‐summer cyanobacterial blooms, this impact on secondary production has the potential to undermine Lake Erie's ability to sustain important ecosystem services.

Lake Erie↗